1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material and a method for forming color images by using this material, and more particularly to a silver halide color photographic light sensitive material which can provide color prints excelling in sharpness, having but only a little coloring at the cut edges, and involving but small chromatic aberration of scanning periphery at scanning exposure system, and also to a silver halide color photographic light-sensitive material which excels in surface smoothness and surface gloss, which has resistance to degradation on performance under extended storage period, and which can form high-quality images, and also to a method for forming color images by using this material.
2. Description of the Related Art
Color photographs are very popular today. Thanks to the advances in the manufacture of light-sensitive materials and also in the techniques of processing, color photographs can be available quickly and almost anywhere. In particular, color photographic printing paper used in making color prints for exhibition can now be processed at high speed due to the water-resistant characteristic of the paper support which are coated with resin on both sides, the light-sensitive material using high-silver chloride emulsion, and the method of processing the material. Both the material and the method are disclosed in PCT International Publication WO 87-04534.
Technical development has been made to increase the processing speed, as well as to enhance the image quality of print images. The image quality of color prints commercially produced at present is fairly good because of improvements which have been made thus far. There is the demand, however, to further heighten the image quality of color prints.
Image quality of color images depend on various properties such as gradient reproduction, color reproduction, graininess, sharpness, and the like. Of these, sharpness is an important property since it determines the degree in details and stereoscopic expression of the resultant image. Therefore, there has been the demand for techniques to enhance the sharpness of color images.
However, the enhancement in sharpness achieved in the recent development of techniques of color-print materials cannot be considered sufficient, largely because of the properties of the paper support which are coated with polyolefin resin for the purpose of processing the material easily and quickly. The color image formed on photographic paper whose support consists of a paper coated with a water-resistant resin is inferior, in terms of sharpness, to the color image formed on the conventional photographic paper whose support consists of a paper coated with baryta. This is because the water-resistant resin layer covering that surface of the support on which light-sensitive emulsions are coated only has a small amount of white pigment kneaded in the resin. The insufficiency of white pigment is believed to cause the light applied to the material during the exposure process to scatter and disperse, resulting in deterioration of image.
Some attempts, not to say many, have been made to compensate for the deficiency of the supports which consist of the paper coated with a water-resistant resin.
Techniques of increasing the amount of white pigment dispersed in polyolefin resin are disclosed in, for example, JP-A-51-6531, JP-A-52-35625, JP-B-55-108658, JP-A-55-113039 and JP-A-57-151942. ("JP-A" means Published Unexamined Japanese Patent Application, and "JP-B" means Published Examined Japanese Patent Application.) Although these techniques improve sharpness, the pigment dispersion in the resin becomes less obvious as the white pigment content increases. Probably due to this insufficient pigment dispersion, the resin coating layer is likely to have defects such as micropores during its forming, ultimately deteriorating the surface gloss or surface smoothness of the the water-resistant resin layer covering that surface of the paper. Consequently, the technique does not serve to sufficiently increase the white pigment content.
Techniques of more increasing the white pigment content are disclosed in JP-A-57-27257 and JP-A-57-49946. In these techniques, a mixture of a white pigment and a composition which can be curable when irradiated with an electron beam is coated on a support, and an electron beam is irradiated to the coating, thereby to form a water-resistant resin layer. With these techniques, however, it is difficult to produce supports for light-sensitive materials in large quantities, making it hard to provide inexpensive supports.
Other methods of increasing the white pigment content are disclosed in JP-B-57-53937, JP-A-50-44818, JP-A-57-64235, and JP-A-59-177542. In these methods, a hydrophilic colloid layer containing a white pigment is interposed between a polyolefin-coated paper support and a light-sensitive silver halide emulsion layer. When the methods are employed, the white pigment content in the hydrophilic colloid layer can be increased to enhance the sharpness of color images. These method, however, have certain disadvantage as the coating amount of a white pigment is increased. First, it is difficult to produce supports for light-sensitive materials in large quantities. Second, the supports obtained exhibit only a small flexural strength.
European Patent EP-0,507,489 describes that smooth resin-coated water-resistant paper supports excelling in surface gloss can be obtained by covering raw paper with a water-resistant resin which comprises 70% by weight or more of polyester and titanium dioxide dispersed in the polyester. However, when a reflective support is made as described and then coated with high-silver chloride emulsions suitable for high-speed processing, the print samples processed, which are yet to be not colored, will be colored at the cut edges. Once such coloring has occurred, the whiteness of the prints will be greatly impaired at the edges if the prints are piled one upon another. As a consequence, their quality, and thus their commercial value, will be reduced.
Therefore, it has been demanded that techniques be developed to enhance the sharpness of color images, wherein using a water-resistant resin-coated paper supports which are suitable for easy and speedy processing can be used without impairing other properties of the color images.
A color photograph is a dye image obtained by the reaction of dye-forming couplers with the oxidized form of development agent produced by which a light-sensitive material comprising a support having provided thereon dye-forming couplers and silver halide emulsions is developed with a color developing agent of aromatic primary amine series.
In the color photograph business, there is a strong demand for systems to perform easy and speedy color processing. A number of improvements have been made, and new systems capable of performing faster color processing have been developed, each every few years.
To increase the processing speed, it is necessary to shorten the periods of the process steps, i.e., color development, bleach-fixing, washing, and drying. A method of increasing the processing speed is disclosed in PCT International Publication WO 87-04534. In this method, a color photographic light-sensitive material using high-silver chloride emulsions as photographic emulsions is processed at high speed. The publication teaches that the use of high-silver chloride emulsions is desirable for the purpose of increasing the processing speed.
Thanks to these efforts, methods of forming an image of high-quality images easily are now widely employed, all of which involve color negative images are printed on silver halide color photographic printing paper coated with high-silver chloride emulsions.
In recent years, it has become possible to provide prints in various sizes, such as panorama size, high-vision size, and the like, to meet the variety of users' needs. Not only is there a demand for various sizes, there is also a demand for various textures such as smoothness and gloss in the printing material. Supports which may satisfy the latter demand are being developed at present.
European Patent EP-0,507,489 describes that polyester may be used as a water-resistant resin to prepare print supports which are superior, in terms of surface gloss and surface smoothness, to the conventional ones prepared by using polyolefin.
The inventors hereof have conducted research in order to provide a silver halide color photographic light-sensitive material, especially color printing paper which excels in gloss and surface smoothness. As a result, they found that the print supports prepared by using polyester as a water-resistant resin had surface gloss and surface smoothness improved over those of the conventional print supports prepared by using polyolefin, but the resultant light-sensitive material became more likely to be desensitized when applied with a pressure, as it was when stored over a long period of time.